no, no - that is exactly what I'm saying. Tab #1 (speedometer1) and #3 (chart2) have non-standard icons whereas #2 (team) and #4 (more) are from the standard icons. When I leave them as they are then I get this:

And regarding the inclusion of your own icons, you have to install a software which can create fonts and then create your own font using your pictos.
Another solution is to resuscitate the pictos-iconmask mixin in your customised theme and to use it for your custom icons. It also means having to do the work twice when wanting to theme those icons.
EDIT: From the 2.2 documentation, use http://icomoon.io to create your icon fonts.